How can Sola Scriptura be a legitimate precept when it has led to such diversity of practices and beliefs?
How many different protestant denominations are that each claim to be "Bible Believeing", yet have such a difference between them.
Perfect example: This woman is sueing her former church over their performance of a gay marriage> http://religion.blogs.cnn.com/2010/06/24/gay-marriage-splits-african-american-church/
Westboro baptist has a slightly different view.
Both claim to be Sola Scriptura.
There really isn't that much difference in beliefs wrt orthodoxy in Protestantism - There is the great Arminian/Calvinist divide, and the Anglican/Lutheran strains, whose liturgical base makes them a way-point somewhere between you and I (while still accepted politely among the Protestants and Evangelicals)... There is a difference in hierarchical vs. congregational order... Other than that, it is more a matter of emphasis than disagreement.
Where there is disagreement, it is usually a matter of apostasy taking hold, or matters wherein the greater apostasy of Rome was not rejected... Bearing in mind, of course, that none are without the stain of Rome. It is well and good that the Protestants protested. It's just that they did not protest enough.